This trip, however, they got into a few spats on where each other was playing...
They're such good pianists... and they love having their picture made or a video made while they play.
This is what I did to solve their problem... I put a tie from some bulk food in the middle of the keyboard. They each had to stay on one side of the tie. Made me think of when our kids were young and we'd have to make a line, somehow, in the car...so one or the other didn't get on someone else's side.
After the duel was solved, it was time to abandon the piano...at least for now.